抄録
This paper reports on the experimental technique, based on thermographic measurements, to calculate the thermally induced positioning errors of the ball screw feed drives in machine tools. To compensate a thermal expansion of the ball screw, its temperature must be known with respect to its position, since the local temperature depends on the traversing program. The temperature increases were measured using resistance thermometers at several points of the ball screw. However, to obtain full temperature profile of the ball screw, the field of temperature was measured by infrared camera. Image processing of obtained thermographic snapshots was carried out using software MATLAB. Program enables to calculate temperature and its coordinate along an arbitrarily selected line. Thus the instantaneous temperature profiles along the ball screw are determined. A closed loop FEA was accomplished together with measurement. The programmed loop consists of thermal analysis followed by structural analysis. So the induced axial force is computed. It enables updating of heat sources according to instantaneous structural condition, so the non-steady heat sources in bearings are taken into account.
